The present invention relates to electric circuit breakers and, more particularly, to novel operating and latching mechanisms for facilitating manual and automatic operation of electric circuit breakers designed to carry relatively high currents.
Automatic electric circuit breakers of relatively high current carrying capacity must necessarily utilize rather large movable contact arm assemblies to carry the current. Moreover, substantial contact pressure must be exerted on the movable contact arms by rather powerful mechanism springs in order to achieve intimate electrical contacting engagement between the fixed and movable contacts of the circuit breaker. Powerful mechanism springs also must be used to achieve abrupt separation of the circuit breaker contacts for requisite high interrupting capacity.
Such powerful mechanism springs pose difficulties to the user in manually articulating the operating mechanism to its reset condition, thus loading the mechanism springs incident to reclosing the circuit breaker. To facilitate manual circuit breaker operation, various mechanical mechanisms interfacing the operating handle and the operating mechanism have been proposed to afford some degree of mechanical advantage. Such mechanical mechanisms have in the past typically been cumbersome to operate, bulky and/or expensive to manufacture.
It is accordingly an object of the present invention to provide an electric circuit breaker of relatively high current carrying capacity which utilizes a relatively compact and simplified operating mechanism readily conducive to manual articulation against the bias of powerful operating mechanism springs.
An additional object of the invention is to provide a circuit breaker of the above character, wherein the operating mechanism thereof is readily articulated via a rotary operating handle.
A further object is to provide a circuit breaker of the above character, wherein resetting of the operating mechanism against the bias of powerful mechanism springs is achieved via a single crank of the rotary handle through a relatively small angle.
Yet another object of the present invention is to provide a circuit breaker of the above character, which includes an improved latching mechanism capable of accommodating a variety of manually and automatically initiated trip functions.
An additional object of the present invention is to provide a circuit breaker of the above character, which is inexpensive to manufacture, compact, and efficient in both its manual and automatic operating modes.
Other objects of the invention will in parts be obvious and in part appear hereinafter.